Ezekiel 40:3

‘And he brought me there, and behold there was a man whose appearance was like the appearance of brass, with a line of flax in his hand, and a measuring reed, and he stood in the gate.'

The man's appearance ‘like the appearance of brass' depicts him as a heavenly visitor (compare Ezekiel 8:2). He was glorious in his appearance. The line of flax was for measuring distances, the measuring reed for more exact measurements. He was there to measure the temple  that was already there  and stood ready at the gate. The fact that the measurement began at the gate may be seen as stressing that it was the making available of the people's access to God that was primarily in mind.

We should note again that there is nothing here to indicate that attempts were to be made to build such a temple, nor that it should be built. It was already there in vision, and the fact that it could be measured was to deliberately indicate its ‘real' presence and the intention for it to be currently effective. It indicated heavenly activity taking place on earth in a form usually invisible, as with Jacob's ladder which provided access to heavenly beings from some spiritual realm and was no doubt to be seen as continuing even when Jacob saw it no more (Genesis 28:12) and providing a similar way to God which was no doubt seen as equally invisibly permanent. Jacob saw Bethel as the house of God and the gate of Heaven (Genesis 28:17). And it was from then on looked on as a sacred sanctuary. How much more this new temple. It is a vision of that other world in its relationships with man (compare also 2 Kings 6:17. See also Daniel 10:13; Daniel 10:20; Zechariah 1:7).